加权反馈控制下的反激变换器小信号模型分析

Small-Signal Modeling of Flyback Converters with Weighted Feedback

采用加权反馈的方法对多路输出反激变换器进行电压反馈控制,提高了多路输出反激变换器的电压输出精度。同时,搭建了基于UC3845、TL431及PC817配合使用的反激变换器,分析了该反激变换器各个部分的工作原理。同时,经过对反激电路各个部分的仔细分析,推导出了在断续工作模式(DCM)下的工作的反激变换器的小信号动态数学模型。最后,搭建仿真电路和实验平台进行PSIM仿真分析和实验研究。仿真和实验结果都验证了该反激变换器工作的可行性和稳定性,同时,具有较高的电压调整率和负载调整率。

This paper uses the method of weighted feedback for multiple-output flyback converters to realize voltage feedback control,improved the output voltage precision of multiple-output flyback converters.In addition,the flyback converter was established based on UC3845,tl431 and PC817,and analyzes the working principle of the flyback converter.After a careful analysis of each part in the flyback circuit,a smal-signal model of the converter under the discontinuous conduction mode has been developed.